Oscillation-receiving device.



G. W. PICKA'RD. OSCILLAT'ION RECEIVING DEVIC E. APPLICA'HON FILED owe, me.

Patented Apr. 20, 1915.

111 Van tor:

CENTER GREENLEAF WHITTIER PICKARILOF AMESBURY, MASSACHUSETTS. ASSIGNOR TO WIRELESS SPECIALTY APPARATUS COMPANY, OF BOSTON, MASSACHUSETTS, A

CORPORATION OF NEW YORK.

OSCILLATION-RECEIVING DEVICE.

Specification of Letters Patent. Patqgnted Apr; 20, 11915.

Original application filed July 24, 1911, Serial No 640,106. Divided and this application filed December E},

" 1913. Serial No. 805.238.

To all-107mm it may concern:

Be it known that I, GREENLEAF \VI-n'r'rma PICKARD, a citizen of the United States of America, and a resident of Amesbury, Massachusetts, have invented certain new and useful Improvements in Oscillation-Receiving Devices, the principles of which are set forth in the following specification and accompanying drawing, which disclose the form of the invention which I now consider to be'the best of the various forms in which the principles of the invention may be embodied.

This invention relates to wireless telegraphy. detectors of the rectifier type, as now well known in the art, the object being to improve the electrical stability of the device; and is also a division of my application for patent Serial Number (340,106, filed July 24th, 1911, and relates particularly to a contacting member for the silicon member, which consists of a mixture, chemical compound or alloy, of two or more of the three elements hereinafter specified, such forexample as arsenic and antimony.

The invention consists in employing, in cooperation with the rectifying substance, another substance in contact therewith which possesses peculiar properties which result in very greatly improving the electrical stability of the device which includes the rectifying material.

Of the drawings, Figure 1 is a vertical section of an apparatus embodying the invention, and Fig. 2 is a vertical section taken transversely through A, B, Fig. 1. 7

Electrical instability has been a wellknown fault of the rectifier type of detector. That is, it has been found in practice that electrical currents or oscillations materially.

stronger than those of received signals, and such as static or atmospheric, and even received signals themselves when the sender is in close proximity to the detector, tend to reduce or even totally destroy the rectifying power of a detector in a g ven contact adjustment. This, of course, is a serious thing in commercial telcgraphy, because it requires a new contact ad] ustmcnt, which it may not be possible to obtain until after a large part of the message has been lost. The present invention removes that fault byproducing a combination which remains in operative adjustment under sub stantially all conditions which v have previously caused instability.

I have found that the invention is best exv ecuted by employing as the substance in contact with the rectifying material, a conductor which is characterized by considerable brittleness, such that at all times there is presented to the rectifying material a suitably small point of a rough or unpolished surface resulting from the fact that the brittle substance breaks off by use instead of becoming smooth or polished] Furs ther than this present hypothesis, the reason is as yet obscure why, for a given adjustment, such class of materials makes the invention produce electricalstability, but it seems to be due to the fact that a suitably small contact can always exist. The fact is that all the materials which produce the desired re sult are characterized by extreme brittleness, and all of them I have found so. far are included in a peculiar new class (brittle) of the materials classified by Mendeljeff inf his well-known, period-law table. (HOW'.

ever, I do notwish to be understood as asserting that thebrittleness necessarily has any. essential relation to the operation.) Specifically the materials most usefulv within the invention, are the following conductors, i. 6., the metals arsenic (As), antimony (Sb) and bismuth (Bi), the best of which seems to be As. On reference to Mendeljeffs table, it will be seen that all these are comprised in group V and in the odd-numbered series therein; 6. (2., As is in the fifth series of group 5, Sb is in'the seventh series of group 5, and Bi is in the eleventh series of group 5. The materials under the even-numbered series seem not so well adapted for use in the invention, although of course, I desire to include in the claims, all materials which are so adapted in greater or less degree. However, the materials which now seem most useful under the invention, are included in said special class of Mendeljeifs group 5 and are characterized by extreme brittleness, as well as by other properties, among which are that there normally exists a tarnish or oxid coat on any exposed surface of these materials; and in use under the invention it is this tarnished surface which is used in contact with the rectifying material, that is to say, the surface becomes tarnished so quickly that notwithstanding the readiness of fracture, the fracture surface becomes tarnished al most immediately, and I do not assert that the tarnish has anything to do with the action of the device.

The rectifying material which up to the present time I have found to be most usefully employed in combination with these brittle conductors, is the element silicon, and particularly when used with a substantially rough or unpolished surface, such as an ordinary fracture face, in contact with the arsenic-and antimony mixture.

The drawings show a detector-holder of substantially the construction shown in my prior Patent 912,726, dated February 16th, 1909. The rectifying material S, such as silicon, and the cooperating conductor A, such as arsenic and antimony, are held, pref erably by soft readily fusible metal, in cups, one or both of the cups being adjustable so that contact selection may be had between S and A. As shown, the silicon preferably has a rough surface presented to A. Likewise, the surface of the brittle conductor A which is presented to S, is rough, produced as by'making a fracture.

So far as I have determined as yet, the cof-operating contact members of this invention 3 do not of themselves have the characteristic of rectifying, except as to such extent as may be due to the tarnish on their surfaces.

Hence their function is substantially limited tc'that of furnishing a stable contact for the other or rectifying member; although it would notice a departure from the invention to employ a material which also rectified in addition to executing the functions of the cooperating contact members of the invention. i

Of course, the invention may be embodied in various mechanical forms, and by way of illustration, reference is here made to another desirable form. which consists in employing one of the brittle conductors, such as arsenic and antimony to the sleeve 7 (or as a lower part of such sleeve) of Fig. l of my prior Patent 830,531 dated November 20th, 1906. Preferably a small mass of the arsenic and antimony is soldered or welded to the lower end of the sleeve 7, and the contact surface of the arsenic and antimony roughened as by making a fracture face.

The invention is not of course, limited to the elements arsenic and antimony, etc., but includes all materials which possess the properties of the same which are useful in the invention; and such materials may include conducting chemical compounds or alloys which possess such properties although the constituents thereof might lack such properties.

The expression rough surface in the claims, implies, as stated above, that the operative portion is probably a single point effectively projecting from such surface.

I claim:

1. As an oscillation receiver, the combination with a rectifying member, of a member contacting therewith and containing arsenic and antimony.

2. As an oscillation receiver, the combination with a member containing the element silicon, of a member contacting therewith and containing arsenic and antimony.

3. As an oscillation receiver, the combination with a member consisting of the element silicon, of a member contacting therewith and containing arsenic and antimony.

GREENLEAF Wlll'lTIElt lICK/lltl).

In presence of \ViLmaM J. BARKLEY, M. C. I'IANNON. 

